In the deployment of wireless mobile stations, especially in VoWLAN roaming situations, seamless handover depends on solving a host of wireless access issues for the end user. Equipment and devices must be configured to negotiate many different frequencies, protocols, technologies, network types, regulatory environments and more, simultaneously not making the underlying complexity transparent to the end user, so as to ensure a truly seamless performance for the user.
It is known that VoWiFi (Voice over Wireless Fidelity) is generally a WiFi based VoIP service. Where VoIP consists of the hardware and software that enable people to use the internet as the transmission medium for telephone calls. VoWiFi is the wireless version of this technology which is designed to work on wireless devices such as a laptop of PDAs.
Many cellular phone companies such as Nokia® and Motorola® have already announced dual-mode cellular phones that will support seamless transaction from WiFi to cellular networks when WiFi is unavailable to a caller. One of the biggest challenges facing VoWiFi is effective roaming access. A WiFi access point offers a communication range of up to 90 meters (commonly called a hotspot), and continuous conversations would mean that the caller must stay within an area of overlapping hotspots, or as already suggested, have a VoWiFi dual-mode phone that would switch to a regular cellular phone transmission when the caller moves out of a hot spot range.
It is desirable to provide a roaming controller which is devoid of the issues in prior art in ensuring seamless roaming especially in VoWLAN situations.